1、定义一个返回 sessionFactory 的公共类

HibernateUtil.java

package com.bjsxt.util;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtil
{
    private static SessionFactory sessionFactory;
    
    static
    {
        sessionFactory = new Configuration().configure().buildSessionFactory();
    }
    
    public static SessionFactory getSessionFactory()
    {
        return sessionFactory;
    }
}

2、CRUD 操作示例

package com.bjsxt.dao.impl;

import java.util.List;

import org.hibernate.Session;
import org.hibernate.SessionFactory;

import com.bjsxt.dao.UserDao;
import com.bjsxt.entity.User;
import com.bjsxt.util.HibernateUtil;

public class UserDaoImpl implements UserDao
{
    //新增
    @Override
    public boolean save(User u)
    {
        try
        {
            SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
            Session session = sessionFactory.getCurrentSession();
            session.beginTransaction();
            session.save(u);
            session.getTransaction().commit();
            return true;
        }
        catch (Exception e)
        {
            e.printStackTrace();
            return false;
        }
    }
    
    //基于条件查询
    @Override
    public boolean checkUserExistsWithName(String username)
    {
        SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
        Session session = sessionFactory.getCurrentSession();
        session.beginTransaction();
        long count = (long) session.createQuery("select count(*) from User u where u.username= :username")
                .setString("username", username)
                .uniqueResult(); // //当确定返回的实例只有一个或者null时用uniqueResult()方法
        session.getTransaction().commit();
        if (count > 0)
        {
            return true;
        }
        return false;
    }
    
    //查询所有
    @Override
    public void queryAll()
    {
        SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
        Session session = sessionFactory.getCurrentSession();
        session.beginTransaction();
        List list = session.createQuery("from User").list();
        for(int i=0;i<list.size();i++)
        {
            User user=(User)list.get(i);
            System.out.println(user.getId()+"："+user.getUsername());
        }
        session.getTransaction().commit();
        System.out.println(list);
    }
}